(19)

(11)

EP 0 256 024 A1

(12)

(43) Date of publication: 24.02.1988 Bulletin 1988/08 (21) Application number: 86907094.0 (22) Date of filing: 31.10.1986

(51) International Patent Classification (IPC):  C08G 65/ 00( . ) C08G 65/ 32( . ) (86) International application number: PCT/US1986/002345 (87) International publication number: WO 1987/002995 (21.05.1987 Gazette 1987/11)

(84) Designated Contracting States: BE DE FR GB IT NL (30) Priority: 08.11.1985 US 19850796624 (71) Applicant: EXFLUOR RESEARCH CORPORATION Austin, TX 78712 (US)	(72) Inventors: LAGOW, Richard, J. Austin, TX 78731 (US) BIERSCHENK, Thomas, R. Roundrock, TX 78681 (US) JUHLKE, Timothy, J. Roundrock, TX 78664 (US) KAWA, Hajimu, M. Austin, TX 78758 (US) (74) Representative: Holdcroft, James Gerald, Dr., et al  Graham Watt & Co., Riverhead Sevenoaks, Kent TN13 2BN Sevenoaks, Kent TN13 2BN (GB)